Electric heating device, especially for use in motor vehicles

Abstract

The present invention relates to an electric heating device which is especially conceived as a heating device for use in automotive vehicles. A plurality of heating elements, which are stacked so as to define a heating block, form together with a control device a structural unit. For this purpose, the control device is accommodated in a lateral bar of the frame by means of which the heating elements are held together. The air to be heated flows through the heating block as well as through windows provided in the lateral bar, past cooling elements which are respectively connected to the power-electronics components of the control device.

What is claimed is:  
     
       1. An electric heating device, especially for use as a supplementary electric heating for motor vehicles, comprising: 
       a plurality of heating elements ( 2 ) which are combined so as to form a heating block, said heating block being held in a rectangular frame ( 3 ,  4 ,  5 ), and  
       a control device for controlling the heating elements ( 2 ), said control device defining a structural unit with the heating block held in the frame ( 3 ,  4 ,  5 ) and being provided with power transistors ( 11 ) which are arranged on a printed circuit board ( 10 ) and which are each provided with a cooling element ( 6 ), wherein  
       the frame is defined by opposed longitudinal bars ( 3 ) and lateral bars ( 4 ,  5 ) arranged at right angles to said longitudinal bars ( 3 ),  
       at least one of said lateral bars ( 5 ) is implemented as a box which is open on one side thereof and which is adapted to have the control device inserted therein,  
       window openings ( 7 ) are provided in said lateral bar ( 5 ) and  
       the cooling elements ( 6 ) of the power transistors ( 11 ) are located between respective opposed window openings ( 7 ) in the inserted condition of the control device.  
     
     
       2. An electric heating device according to  claim 1 , wherein means ( 17 ) for influencing the air current are provided between said opposed window openings ( 7 ). 
     
     
       3. An electric heating device according to  claim 1 , wherein the cooling elements ( 6 ) are each U-shaped and wherein the respective opposed legs of the cooling elements ( 6 ) are arranged adjacent the window openings ( 7 ) in the inserted condition of the control device. 
     
     
       4. An electric heating device according to  claim 3 , wherein air-conducting means ( 17 ) are provided between said opposed window openings ( 7 ) said air-conducting means projecting between the legs of the U-shaped cooling elements ( 6 ). 
     
     
       5. An electric heating device according to one of the claims  1 , wherein each cooling element ( 20 ) has a pin ( 20   a ) which, extending through an opening provided in the printed circuit board ( 10 ), establishes a connection between said cooling element ( 20 ) and the transistor ( 19 ). 
     
     
       6. An electric heating device according to one of the claims  1 , wherein each of the cooling elements ( 20 ) is secured in position by means of a spring ( 21 ). 
     
     
       7. An electric heating device according to one of the claims  2 , wherein the window openings ( 7 ) and/or the means ( 17 ) for influencing the air current are implemented such that air can flow around components of the control device which are located on the printed circuit board ( 10 ). 
     
     
       8. An electric heating device according to one of the claims  1 , wherein the printed circuit board ( 10 ) of the control device is equipped with components on only one side thereof. 
     
     
       9. An electric heating device according to one of the claims  1 , wherein the printed circuit board ( 10 ) is arranged at right angles to the plane of the frame and is implemented such that its length corresponds substantially to that of the lateral bar ( 5 ). 
     
     
       10. An electric heating device according to one of the claims  1 , wherein the control device is adapted to be fixed in the lateral bar ( 5 ) by means of electric connection lugs ( 15 ) which project from the heating elements ( 2 ) into the interior of said lateral bar ( 5 ). 
     
     
       11. An electric heating device according to  claim 10 , wherein spring elements ( 14 ) for receiving the connection lugs ( 15 ) are provided on the printed circuit board ( 10 ), said spring elements ( 14 ) being complementary to the connection lugs ( 15 ). 
     
     
       12. An electric heating device according to  claim 1 , wherein the open side of the box-shaped lateral bar ( 5 ) can be closed by means of a plug-on or clip-on cover.